Re: route cache DoS testing and softirqs

From: Robert Olsson
Date: Wed Mar 31 2004 - 17:39:33 EST

Andrea Arcangeli writes:

> Maybe the problem is simply that NAPI should be tuned more aggressively,
> it may have to poll for a longer time before giving up.

It cannot poll much more... 20 Million packets were injected in total
there were 250 RX irq's. Most from my ssh sessions. There are some TX
interrupts... it's another story

Packet flooding is just our way to generate load and kernel locking must
work with and without irq's. As far as I understand the real problem is
when do_softirq is run from irqexit etc.

Some thoughts...

If we tag the different do_softirq sources (look in my testpatch) we can
control the softirqs better. For example; do_softirq's from irqexit etc
could be given low a "max_restart" this to move processing to ksoftird
maybe even dynamic.

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